What mass of CO2 will be produced when 50 g of CaCO3 decomposes?

CaCO₃ decomposition:

CaCO₃ -> CaO + CO₂

The first thing to do here is to calculate the relative formula mass of CaCO₃ and CO₂.

RFM of CaCO₃ = 40 g + 12 g + (16 g x 3) = 100 g

RFM of CO₂ = 12 g + (16 g x 2) = 44 g

The decomposition equation shows 1 CaCO₃ goes to 1 CaO and 1 CO₂.

We have 50 g of CaCO₃, effectively we have half a CaCO₃.

50 g / 100 g = 0.5

In order to get the mass of CO₂ we need to times the RFM of CO₂ by 0.5 (or divide by 2) because of the ratio of CaCO₃ to CO₂:

44 g x 0.5 = 22 g

22 g of CO₂ are obtained from decomposition of 50 g of CaCO₃.